Industrial and power generation turbomachines include a casing that houses a turbine. The turbine includes a plurality of rotor blades, or buckets, positioned along a gas flow path through the turbine, the blades supported by a number of turbine rotor wheels. The rotor blades and wheels define a plurality of turbine stages. Turbomachines also include one or more combustors that generate hot gases. The hot gasses may pass through a transition piece toward the plurality of turbine stages. In addition to hot gases from the one or more combustors, gases at a lower temperature flow from a compressor toward a wheelspace of the turbine. The lower temperature gases provide cooling for the rotor wheels as well as other internal components of the turbine. In order to prevent hot gases from entering the wheelspace, the turbine includes near flow path seals arranged between adjacent rotor wheels or rotor blades. The near flow path seals may be configured to fit closely adjacent the rotor wheels or rotor blades to reduce the leakage of hot gasses from the gas path into the wheelspace.
Generally, each of the rotor blades for a given stage in the turbine are attached to the respective rotor wheel using a dovetail assembly—i.e., the base of the rotor blade has a shape that is complementary to a slot in the rotor wheel—allowing the dovetail end of the rotor blade to slide into the dovetail slot in the rotor wheel and be held in position during operation of the turbine. Additionally, in certain turbines the near flow path seals may be attached at their base to rotor wheels using a similar dovetail assembly. Such a construction can ensure proper alignment of the rotor blades and near flow path seals during operation of the turbomachine. However, once all of the near flow path seals are installed for a given seal member rotor, the base of the seals may not be easily accessible.
Such a construction may create some difficulty when, for example, a maintenance worker needs to remove one or more of the near flow path seals. Further, each dovetail slot in the near flow path seal rotor wheel may include a C-shaped seal in the root for sealing the slot. The C-shaped seal necessitates applying a high force to the near flow path seal to remove it from the dovetail slot. The removal of near flow path seals is currently carried out in three ways. In later stages of the turbomachine, space is sufficient to allow installation and use of a hydraulic operated removal system (such as disclosed in U.S. patent application Ser. No. 14/277,232, filed May 14, 2014, and currently pending). At early stages of many turbomachines, such as between first and second stages and second and third stages, the space constraints prohibit use of the hydraulic operated removal system for removal of near flow path seals. In these situations, in one approach, the removal process is performed by hand with the force applied with a hammer, which makes it nearly impossible to remove the near flow path seals without damaging the component and surrounding structure. In order to address this situation, US patent application publication 2015/0260043, filed Mar. 12, 2014, discloses a removal tool for near flow path seals that operatively slides into a dovetail in a rotor wheel adjacent to the near flow path seal as the tool pulls on the near flow path seal. This approach has been found to be non-functional for a number of reasons, most notably, because the path of the adjacent rotor wheel dovetail is misaligned with the ideal path in which to pull the seal to remove it from its dovetail. This approach can also cause damage to the seal.